Neumann worked at the firm for 10 years but left last August for a career break.
Hull will be responsible for the execution-only and advisory business as well as distributor and business partner relationships. Previously he headed up Fidelity Direct and held roles at Scottish Widows, Lloyds TSB, Prudential, Barclays and LEK Consulting.
Bestinvest chief executive John Spiers says: “These senior level appointments underline how vital our discretionary management, advisory and web-based services are to our offering. We are absolutely delighted to welcome such high-calibre recruits to the Bestinvest team and the move reinforces our commitment to introduce fresh thinking and add value to our clients.”